Measure authorizes distributors to reduce generation at risk to the system; The objective is to avoid instabilities on low load days
A approved this Tuesday (18.nov.2025) the emergency plan presented by (National System Operator) to allow temporary generation cuts in Type 3 plants when there is a risk to the operational safety of the electrical system. The mechanism will be applied in situations of low net load – these occur, above all, on days of strong solar irradiation, mild temperatures and high production of MMGD (distributed micro and mini generation).
A low net load scenario is seen when the country’s total demand decreases at the same time that distributed generation reaches production peaks. As this energy is injected directly into the distributors’ network, the ONS needs to reduce the production of the plants it controls, reducing inertia and margin of maneuver to maintain stable frequency and voltage. In extreme situations, this increases the risk of instability in the (National Interconnected System).
Plants classified as Type 3 are generation projects directly connected to the distribution networks, and not to the transmission system. Therefore, they are not dispatched centrally by the ONS, which means that the operator does not directly control their production.
Brazil operated close to these limits because of MMGD on May 4 and August 10, 2025, when the combination of low demand and high solar generation put pressure on system security, according to the ONS. Generation cutting comes as a security tool for ONS.
THE PLAN
The plan determines that the ONS notifies distributors 2 to 7 days in advance of the possibility of triggering the generation cut. Distributors must then alert Type 3 plants connected to their networks, which are not centrally dispatched by the operator and may have their generation temporarily reduced.
In the 1st phase, 12 distributors with the highest concentration of Type 3 plants will be involved, including CPFL Paulista, Cemig D, Copel D, Energisa MT and Coelba, responsible for around 80% of the capacity of this type of generation. Other companies may be included later.
Aneel determined that these distributors must prepare, within 20 days, operating instructions compatible with the plan and send an updated inventory of their capacity to implement cuts.
The ONS must present technical reports to the agency after each activation and will have a reduced period of time to consult society on urgent operational adjustments. The SFT (Superintendency of technical inspection of Services and Electric Energy) will monitor the entire implementation.
The director-rapporteur, stated that the plan makes the process more transparent and strengthens coordination between distributors and ONS, reducing risks of instability and protecting consumers.
